Upon the
U.S. entry into
World War I in 1917, Cooper enlisted in the Second Tennessee Infantry,
National Guard, and was commissioned a
first lieutenant. Later he was transferred, with his company, to Co K, 119th Infantry, Thirtieth Division, and served in
France and
Belgium. On July 9, 1918, he was promoted to
captain and served as
regimental
adjutant until discharged from the army on April 2, 1919. After the war he resumed the practice of law in Dyersburg. Cooper was a member of the
city council and city attorney from 1920 to 1928, and was elected department commander of the
American Legion of Tennessee in 1921. Elected as a Democrat to the
71st, and to the fourteen succeeding,
Congresses, Cooper served from March 4, 1929, until his death. He served as chairman of the
U.S. House Committee on Ways and Means (
84th and
85th Congresses), and on the Joint Committee on Internal Revenue Taxation (Eighty-fifth Congress). He was a signatory to the 1956
Southern Manifesto that opposed the desegregation of public schools ordered by the Supreme Court in
Brown v. Board of Education. ==Death==